Scientists in Australia who reviewed over 30 trials found that taking aspirin during pregnancy may modestly reduce the risk of the mother developing pre- eclampsia, a condition characterized by high blood pressure that can lead to serious complications.
The study is published in the early online edition of The Lancet and was conducted by Dr Lisa Askie, of the University of Sydney and colleagues.
It’s not clear what causes pre-eclampsia, but it could be that chemicals released in the placenta disrupt blood flow in the mother’s blood vessels which in turn triggers an increase in blood platelets, the blood’s natural anti-clotting agents.
Dr Askie and colleagues did a systematic review and meta-analysis on individual patient data from 31 randomized trials looking at the primary prevention of pre-eclampsia that included a total of 32,217 women and their 32,819 babies. Their study is called PARIS, short for Perinatal Antiplatelet Review of International Studies Collaboration.
The participants in the trials took either a low dose aspirin (50 to 150 mg per day), another anti-platelet agent called dipyridamole (brand nae Persantine), a placebo, or no drug at all.
There were some other smaller trials that involved other anti-platelet agents such as heparin and ozagrel.
The results showed that the women who received antiplatelet agents were 10 per cent less likely to develop pre-eclampsia, of delivering before 34 weeks, and of having a serious outcome from the pregnancy compared to women in the control group.
Antiplatelet agents did not affect the risk of death of the fetus or baby, the size of the baby, or bleeding events in either the mothers or their babies.
Also, there was nothing to suggest that particular subgroups of women were more or less likely to benefit from antiplatelet agents than any other.
From a public health perspective, the researchers said, this may give some weight to a case to encourage wider use of anti-platelet agents.
The researchers concluded that:
“Antiplatelet agents during pregnancy are associated with moderate but consistent reductions in the relative risk of pre-eclampsia, of birth before 34 weeks’ gestation, and of having a pregnancy with a serious adverse outcome.”
The study did not look at the long term effects of taking aspirin.
In an accompanying editorial, Dr James Roberts and Dr Janet M Catov of the University of Pittsburgh in the US said that it was difficult to weigh up the benefits against the risk of taking aspirin, especially in the longer term, and that it should be an informed decision made between doctor and patient.
Pre-eclampsia is a serious condition arising in about 1 in 20 pregnancies where the mother’s blood pressure goes up and her urine containes high concentrations of protein (because of kidney problems). It can also give her abdominal pain, headache and swelling.
Pre-eclampsia affects the placenta, and somtimes the mother’s kidneys, liver and brain. When it progresses, seizures can develop, and it becomes eclampsia, the second most frequent cause of maternal death in the US, according to the Centers for Disease Control and Prevention (CDC).
According to the CDC, pre-eclampsia is also a major cause of fetal complications such as low birth weight, premature birth, and stillbirth.
“Antiplatelet agents for prevention of pre-eclampsia: a meta-analysis of individual patient data.”
Lisa M Askie, Lelia Duley, David J Henderson-Smart, and Prof Lesley A Stewart, on behalf of the PARIS Collaborative Group.
The Lancet Early Online Publication, 17 May 2007.
DOI:10.1016/S0140-6736(07)60712-0
Click here for Online Guide to Pregnancy, Birth and Live (Australian website).
Written by: Catharine Paddock
Writer: Medical News Today